特厚煤层相邻工作面开采覆岩运移规律研究

Study on Overlying Strata Movement in Mining Adjacent Working Face of Extra Thick Seam

为了掌握相邻工作面煤层开采后覆岩运移规律,采用FLAC有限元软件模拟某矿相邻工作面先后开采后覆岩应力、位移和塑性破坏特征。结果表明:相邻采空区残余支承压力在中间区段煤柱叠加,煤柱覆岩在极大应力的作用下产生较大的垂直位移和剪切破坏,使得两侧采空区高位覆岩向下同步运动;采空区覆岩随工作面回采呈现"增大-稳定"的拱形破坏,沿倾向形成双拱破坏,其与中间煤柱覆岩较大的剪切耦合形成1个横跨两采空区的破坏拱。最后通过现场钻孔窥视证实覆岩运移破坏特征,并结合经验公式得到相邻工作面开采覆岩"两带"破坏高度取估算上限值更为合理。

In order to master the movement law of overlying strata after coal mining in adjacent working faces,FLAC finite element software was used to simulate the sequential mining of adjacent working faces in a mine,and the stress,displacement and plastic failure characteristics of overlying strata after mining were analyzed.The results showed that the residual supporting pressure in adjacent mined-out areas was superimposed on coal pillars in the middle section,resulting in large vertical displacement and shear failure of overlying strata under the action of maximum stress,resulting in simultaneous downward movement of high overlying strata in both mined-out areas.The goaf overburden presents an"increasing-stabilizing"arch failure with the stoping of the working face,forming a double arch failure along the inclination,and a large shear coupling with the middle pillar overburden forms a destruction arch spanning the two goafs.Finally,the characteristics of overburden migration and failure are confirmed by drilling and peeping in the field,and it is more reasonable to take the estimated upper limit value for the failure height of the"two zones"of overburden mining in the adjacent working face according to the empirical formula.